In six years, Wendy's and Burger King will slide down to the No. 6 and No. 8 positions, respectively, according to the analysts' predictions. McDonald's is expected to maintain its top spot with $43.8 billion in sales, followed by Starbucks ($18.8 billion), Subway ($18.4 billion), Dunkin' Donuts ($11.6 billion), and Chick-fil-A ($10.8 billion).